Demographic processes in a forest roe deer population

Abstract

Studies were made from 1975-1980 of the functioning of a population of forest roe deer Capreolus capreolus (Linnaeus, 1758) in an extensive forest area (about 8,000D ha). The index of potential reproductivity, defined by analysis of the embryos of 71 does, was found to be 1.56 embryos per doe over 21 months old and 1.82 embryos in gestating does. Effective population increase was on an average 66.5% of the whole female part of the population, including yearling females not taking part in reproduction. The estimated index of effective increase was on an average 0.9 fawns per individual capable of reproduction. The natural mortality among adult individuals is due primarily to winters with severe frosts and heavy snowfall. The greatest losses (33.4% and 34.8% of the autumn head of roe deer) were found during the two winters when snow cover persisted for a long time. Mortality is also high among fawns during the first 6 months of life, being on an average 37.6%. Average length of life was found to be 2.9 years, calculated from the life table drawn up on the basis of known mortality among fawns and the age of 250 does, and a survival curve plotted.